Method of rebuilding worn gear teeth by explosive swaging

ABSTRACT

A method of rebuilding worn gear teeth by fitting a metallic driver plate around the top lands of the teeth on a gear and then wrapping a sheet of explosive material around the driver plate. Upon detonation of the explosive material, the driver plate is driven against the gear teeth and the gear teeth are swaged or bulged. The driver plate is then removed and the teeth are then machined or ground to a desired dimension.

United States Patent De Core et al.

[54] METHOD OF REBUILDING WORN GEAR TEETH BY EXPLOSIVE SWAGING [72] Inventors: Fred De Core; Thaddeus A. Peake; Ted R.

Marshall, all of Louisville, Ky.

[73] Assignee: The United States of America as represented by the Secretary of the Navy [22] Filed: June 10,1970

[21] Appl.No.: 45,162

52 us. c1. ..29 401, 29/421 E, 29/34, 29 1592, 72/372, 72 56, 76/51, 113/44 E 51 1111.01. ..B22d 19 10, 823p 7 00 [58] Field of Search ..29/421 E, 401, 34, 159.2; 72/372,-56; 76 51; 113/44 E [56] References Cited UNITED STATES PATENTS 2,367,206 1/1945 Davis ..29 421 E 2,961,357 11/1960 Earnhardt ..29/421E 1.4 June 13, 1972 3,089,230 5/ 1963 Chapman ..29/421 E 3 ,055,095 9/1962 3,286,329 11/1966 3,432,912 3/1969 3,434,194 3/ 1969 Whittaker ..29/421 E FOREIGN PATENTS OR APPLICATIONS 1,221,576 l/1960 France ..72/56 619,451 5/1961 Canada ..29/421 E Primary Examinen-John F. Campbell Assistant Examiner-Donald P. Rooney Attorney-R. SQ Sciascia, H. H. Losche and Paul S. Collignon 57] ABSTRACT A method of rebuilding worn gear teeth by fitting a metallic driver plate around the top lands ofthe teeth on a gear and then wrapping a sheet of explosive material around the driver plate. Upon detonation of the explosive material, the driver plate is driven against the gear teeth and the gear teeth are swaged or bulged. The driver plate is then removed and the teeth are then machined or ground to a desired dimension.

2 Claims, 3 Drawing Figures PATENTEBJUN 13 m2 3, 668 768 FRED DE CORE TH/IDDEUS A. PEA TED R. MARSHA F/G. 2. lay 434% g 5 Puas.

ATTORNEYS METHOD OF REBUILDING WORN GEAR TEETH BY EXPLOSIVE SWAGING STATEMENT OF GOVERNMENT INTEREST The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment'of any royalties thereon or therefor.

BACKGROUND OF THE INVENTION The present invention relates to a method of rebuilding worn gear teeth by explosively upsetting the worn gear teeth sufficiently to allow machining to the original dimensions.

When spur gears have been in service for a considerable length of time, they become worn and must be either replaced or repaired. As very large gears, in particular, are very expensive, it is usually more economical to rebuild worn gears rather than provide new ones. Generally, there are two methods employed for rebuilding worn gears. One method consists of building up the worn gears by heliarc welding and then machining or hobbing .the teeth to the desired dimensions. Another method of rebuilding worn gear teeth consists of manually swaging the worn teeth by peening with a hammer and then machining or grinding the gear teeth to their original dimensions.

SUMMARY OF THE INVENTION The present invention relates to a method for rebuilding worn gears by explosively upsetting the gear teeth and then machining the gear teeth to their desired dimensions. A metallic drive plate is positioned around the top lands of the gear teeth and then a sheet of flexible explosive material is wrapped around the periphery of the drive plate. A detonator is provided to ignite the explosive material and, upon detonation, the driver plate is driven inwardly against the gear teeth with such force that the teeth are swaged or bulged. The gear teeth are then machined, ground or hobbed to their desired dimensions.

It is therefore a general object of the present invention to provide an improved method of rebuilding gear teeth by explosively swaging the worn gear teeth.

BRIEF DESCRIPTION OF THE DRAWING DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawing, there is shown a gear 11 having a plurality of teeth 12 which are worn and are to be restored to their original dimensions. Gear 11 is supported on a suitable mandrel l3 and a steel driver plate 14 is placed around the periphery of gear 11 and in contact with the top lands of teeth 12. The width of driver plate 14 is equal to the width of gear 11, and driver plate 14 is split at 15 to facilitate placement around gear 1 l and later removal. A layer of explosive 16 is positioned around driver plate 14 and a detonator 17, such as an electric blasting cap, is provided for detonating explosive 16. By way of example, the layer of explosive 16 might be Detasheet, a flexible, plastic-bonded form of high explosive manufactured by E. I. DuPont, Wilmington, Delaware. Also detonator 17 might be DuPont detonator E-94, which is designed especially for initiating flexible explosives.

OPERATION a layer of flexible ex losive 16 is positioned around driver plate 14. Detonator l is positioned opposite a gear tooth l2 and, upon ignition, detonator l7 initiates flexible explosive 16 and the force thereof drives driver plate 14 against teeth 12, as shown in FIG. 3 of the drawing. Contact of driver plate 14 with the lands and flanges of gear teeth'l2 causes teeth 12 to be swaged or bulged. Driver plate 14 is then removed and gear teeth 12 are reshaped, as by machining, grinding or hobbing.

The present invention can also be utilized to rework gear teeth of sector gears, that is, gears which do not rotate a full 360. It is merely necessary that a driver plate be provided which is sufficient in dimension to contact all teeth that are to be swaged.

We claim: I

l. A method of rebuilding worn gear teeth comprising:

providing a driver plate in engagement with the top lands of teeth of a gear,

next applying a layer of explosives to the outer perimeter of said driver plate,

next detonating said layer of explosives whereby said driver plate swages said teeth of said gear to dimensions greater than the design dimensions of said teeth, and

then finishing said gear teeth to their design dimensions.

2. A method of rebuilding worn gear teeth as set forth in claim 1 wherein said driver plate is equal in width to the width of said gear teeth and is split to facilitate removal from said gear teeth after detonation of said layer of explosives. 

1. A method of rebuilding worn gear teeth comprising: providing a driver plate in engagement with the top lands of teeth of a gear, next applying a layer of explosives to the outer perimeter of said driver plate, next detonating said layer of explosives whereby said driver plate swages said teeth of said gear to dimensions greater than the design dimensions of said teeth, and then finishing said gear teeth to their design dimensions.
 2. A method of rebuilding worn gear teeth as set forth in claim 1 wherein said driver plate is equal in width to the width of said gear teeth and is split to facilitate removal from said gear teeth after detonation of said layer of explosives. 